In general, on a surface of a printed circuit board, pads, wiring patterns, resists, silkscreen printings etc. are provided and by being attached on a substrate inspection apparatus, the pads, wiring patterns etc. are inspected. As such substrate inspection apparatuses for inspecting pads or wiring patterns on a printed circuit board, various substrate inspection apparatuses have been proposed. For example, apparatuses described in the patent literature 1 or 2 shown below exist.
A substrate inspection apparatus described in the patent literature 1 includes an area discrimination part for discriminating pattern areas on a printed circuit board with respect to a taken image of a printed board and an inspection part having an inspection treatment part for performing a detecting processing of a defect to each pattern area on the printed circuit board. After area information is formed on the basis of colors different at every pattern regions in an area dividing part, an inspection processing part detects a defect at every pattern area by applying different design rules at every pattern area or comparing with a normal reference image. By the configuration, to a pattern area where even a fine defect is not allowed, a strict reference is applied and to a pattern area where a relatively large defect is allowed, a relaxed reference is applied to effectively detect defectives.
In a wiring pattern detection method described in the patent literature 2, a fatal region pattern which shows necessary indispensable regions corresponding to the center of a wiring pattern is compared with an inspected pattern obtained from wiring patterns on an object under test and a defect is detected from the non-coincidence of both patterns. In particular, in the patent literature 2, as shown in FIG. 14 in the patent literature 2, if a crack which intrudes a fatal region pattern P2 exists, it is determined to be defective, on the other hand, if a small crack which does not intrude the fatal region pattern P2 exists, it is determined to be non-defective.
Patent Literature 1: Japanese Unexamined Patent Application Publication No. 11-337498
Patent Literature 2: Japanese Unexamined Patent Application Publication No. 2000-241130